Rdistance - Distance-Sampling Analyses for Density and Abundance Estimation

Distance-sampling analyses (Buckland et al., (2015) <doi:10.1007/978-3-319-19219-2>) estimate density and abundance of survey targets (e.g., animals) when detection declines with distance. Distance-sampling is popular ecology, especially when survey targets are observed from aerial platforms (e.g., airplane or drone), surface vessels (e.g., boat or truck), or along walking transects. Both point and line transects can be analyzed. Outputs include overall (study area) density and abundance, effective sampling distances, and model fit statistics. A large suite of classical, parametric detection functions (e.g., half-normal, hazard rate) is included along with uncommon parametric functions (e.g., Gamma, negative exponential). Non-parametric smoothed distance functions are included. Measurement unit integrity is enforced via internal unit conversion. The help files and vignettes have been vetted by multiple authors and tested in workshop settings.

Last updated 7 months ago

6.51 score 8 stars 40 scripts 313 downloads

mra - Mark-Recapture Analysis

Accomplishes mark-recapture analysis with covariates. Models available include the Cormack-Jolly-Seber open population (Cormack (1972) <doi:10.2307/2556151>; Jolly (1965) <doi:10.2307/2333826>; Seber (1965) <doi:10.2307/2333827>) and Huggin's (1989) <doi:10.2307/2336377> closed population. Link functions include logit, sine, and hazard. Model selection, model averaging, plot, and simulation routines included. Open population size by the Horvitz-Thompson (1959) <doi:10.2307/2280784> estimator.

Last updated 7 years ago

4.37 score 47 scripts 241 downloads